1. Field of the Invention
Embodiments of the present invention relate generally to a method and apparatus for transferring an image sequence from a host system to a client communication endpoint. Specifically, an encoding processor at the host applies lossless and lossy encoding techniques to different portions of frames in the sequence such that commodity video decoder apparatus at the client is enabled to operate in tandem with a decoding processor to produce a client approximation of the image sequence for display.
2. Description of the Related Art
Commodity video decoders are available as hardware (i.e., tailored silicon) or software (i.e., machine executable instructions targeted for general purpose processors). Modern silicon implementations are compliant with well known standards such as H.264 and are generally low power and low cost. While such decoders may comprise a limited masked decoding capability (i.e., an ability to skip decoding sections of an encoded video image as defined by a mask), the mask is inaccessible for exploitation by external functions. While such decoders are well suited to processing relatively low contrast video images, they are poorly suited to processing high definition text content, such as parts of computer desktop display images.
In the field of combined lossless and lossy encoding techniques, various methods exist for encoding selective image parts of a video image e.g., indexed encoding (e.g., color cache techniques), PCM encoding as supported within H.264 or residual encoding, for example as supported by the H.264 High 4:4:4 profile, Such approaches generally require specialized decoder capabilities.
Presently available hybrid decoders can be configured to assemble a mixed content image stream by decoding different image types. These are generally software-oriented and therefore computationally inefficient, or hardware-oriented in which case reliant on complex proprietary processing structures, resulting in added cost to endpoints.
Therefore, there is a need in the art for a method and apparatus for encoding of a mixed content image sequence for communication to a client endpoint, making efficient use of communication resources. The architecture of such a client endpoint should be suited to economically attractive implementations.